This invention relates to a composition which contains proanthocyanidin, as well as to a drink, a food, a cosmetic and a medicament which contain the composition, and a method for stabilizing proanthocyanidin.
Proanthocyanidin is a substance which is contained in many plants and is known to have strong antioxidant action. However, it is known that this substance is unstable in the presence of oxygen. That is, oxidative polymerization etc. rapidly occurs in the presence of oxygen, which discolors the proanthocyanidin.
A known method for stabilizing proanthocyanidin in a wine includes admixing a wine with potassium pyrosulfite. A known method for stabilizing proanthocyanidin in an apple juice includes admixing an apple juice with ascorbic acid. Also, JP-A-6-336420 (the term xe2x80x9cJP-Axe2x80x9d as used herein means an unexamined published Japanese patent application and xe2x80x9cJP-Bxe2x80x9d means an examined published Japanese patent publication) discloses a cosmetic in which sodium hydrogen sulfite, 1-hydroxyethane-1,1-disulfonic acid, and diethylenetriaminepentaacetic acid or phytic acid are employed in order to prevent coloring of proanthocyanidin with passage of time.
In addition, as methods or compositions for stabilizing polyphenol or for preventing their discoloration, (1) JP-B-8-2819 discloses a method for preventing discoloration of polyphenol by mixing a porphyrin-zinc complex and an organic reducing agent, (2) JP-A-5-112441 discloses a cosmetic for the skin in which a polyphenol compound is mixed with a sucrose-higher fatty acid ester, (3) JP-A-5-163131 discloses a cosmetic for the skin in which a polyphenol compound is mixed with an alkyl glucoside and (4) Japanese Patent No. 2,744,572 discloses a method for preventing discoloration of an external skin preparation containing a polyhydric alcohol or saccharides mixed with a polyphenol compound having three or more phenolic hydroxyl groups.
The object of the invention is to provide a method for stabilizing proanthocyanidin, particularly for preventing, for example, its discoloration by oxidative polymerization. The object of the present invention is also to provide a proanthocyanidin-containing composition having excellent stability, as well as a drink, a food, a cosmetic or a medicament which contains the composition.
The invention relates to the following items (1) to (17).
(1) A composition which comprises proanthocyanidin, and an amino acid having a hydroxyl group or a dipeptide containing the amino acid.
(2) A composition which comprises proanthocyanidin and an amino acid having a hydroxyl group.
(3) A composition which comprises proanthocyanidin and a dipeptide containing an amino acid having a hydroxyl group.
(4) The composition according to the item (1), wherein the concentration of the amino acid having a hydroxyl group or the dipeptide containing the amino acid is within the range of from 0.001 to 1% by weight based on the total composition.
(5) The composition according to any one of the items (1) to (4), wherein the concentration of proanthocyanidin is within the range of from 0.01 to 20% by weight based on the total composition.
(6) The composition according to the item (1), (2), (4) or (5), wherein the amino acid having a hydroxyl group is L-serine or L-threonine.
(7) The composition according to the item (1), (3), (4) or (5), wherein the dipeptide containing an amino acid having a hydroxyl group is glycyl-L-serine.
(8) The composition according to any one of the items (1) to (7), wherein proanthocyanidin is derived from a plant belonging to the genus Vitis, Malus, Hordeum, Diospyros, Cocos, Theobroma, Pinus, Vaccinium, Fragaria, Phaseolus or Arachis.
(9) A composition which comprises the composition according to any one of the items (1) to (8) and an additive suited for a drink.
(10) A composition according to the item (9), wherein the drink is a fruit wine, a fruit juice drink or a health drink.
(11) A composition which comprises the composition according to any one of the items (1) to (8) and an additive suited for a food.
(12) A composition which comprises the composition according to any one of the items (1) to (8) and a cosmetically acceptable carrier.
(13) A composition which comprises the composition according to any one of the items (1) to (8) and a pharmaceutically acceptable carrier.
(14) A method for stabilizing proanthocyanidin, which comprises blending proanthocyanidin with an amino acid having a hydroxyl group.
(15) A method for stabilizing proanthocyanidin, which comprises blending proanthocyanidin with a dipeptide containing an amino acid having a hydroxyl group.
(16) A proanthocyanidin stabilizing agent, which comprises an amino acid having a hydroxyl group.
(17) A proanthocyanidin stabilizing agent, which comprises a dipeptide containing an amino acid having a hydroxyl group.